1. Field
The present invention relates to methods of forming semiconductor structures and related manufacturing of semiconductor devices. Some embodiments more particularly relate to methods of forming a thin ferroelectric layer using a polishing process and to methods of manufacturing related semiconductor devices.
2. Description of the Related Art
Since the discovery of ferroelectric materials (e.g., PZT (PbTiO3) or SBT (SiBi2Ta2O9)), research into their use in memory devices and other electronic devices has been of interest. The ferroelectric material has non-volatile characteristics for storing data in the presence or lack of an electrical charge, due to its electrically controllable polarization state.
A ferroelectric random access memory (FRAM) device is an example of a memory device that uses ferroelectric materials. The FRAM device provides the readable and writable functions of a volatile random access memory while also providing non-volatile characteristics for storing data. Current techniques of manufacturing the FRAM device have some deficiencies as compared with techniques of manufacturing a DRAM device, so operational speed of the FRAM device may be dissatisfactory. However, the FRAM device has non-volatile characteristics that retain data while there is a lack of an electrical charge, so the FRAM device may be very useful as a storage unit that provides nonvolatile retention of information. Relative to some nonvolatile devices, the FRAM device may have lower power usage in operation, faster write performance and a greater maximum number of write-erase cycles.
A memory device using a scanning probe (e.g., a ferroelectric hard disk (FeHDD)) may is another example of a memory device that uses ferroelectric materials. The probe memory device may use a ferroelectric material media for its non-volatile characteristics. The probe memory device using the ferroelectric material may be a scaled down substitute for a conventional hard disk. Accordingly, development of a highly-integrated probe memory device using ferroelectric materials is of considerable interest.
Techniques of forming a ferroelectric layer having properties adequate for a memory device are needed. As the integration degree increases and operational voltage decreases in a memory device, formation of a ferroelectric layer having a reduced size while avoiding deterioration of its electrical polarization properties or other electrical properties may be required to realize more highly-integrated memory devices.